'use strict';
const assert=require('assert/strict');
const http=require('http');
const {parsePort,defaultPortCandidates,listenWithPortFallback}=require('../server');

function close(server){return new Promise(resolve=>server.close(()=>resolve()))}
function listen(server,port=0){return new Promise((resolve,reject)=>{server.once('error',reject);server.listen(port,'127.0.0.1',()=>resolve(server.address().port))})}

(async()=>{
  assert.equal(parsePort(undefined),8080);
  assert.equal(parsePort('0'),0);
  assert.equal(parsePort('4312'),4312);
  assert.throws(()=>parsePort('invalid'),/Invalid server port/);
  assert.deepEqual(defaultPortCandidates(8080).slice(0,3),[8080,3000,3001]);

  const blocker=http.createServer((_req,res)=>res.end('occupied'));
  const occupiedPort=await listen(blocker);
  const fallbackServer=http.createServer((_req,res)=>res.end('LinkField'));
  const listening=await listenWithPortFallback(fallbackServer,{host:'127.0.0.1',preferredPort:occupiedPort,explicitPort:false,candidates:[occupiedPort,0]});
  assert.equal(listening.usedFallback,true);
  assert.notEqual(listening.port,occupiedPort);
  const response=await fetch(`http://127.0.0.1:${listening.port}/`);
  assert.equal(await response.text(),'LinkField');

  const explicitServer=http.createServer();
  await assert.rejects(
    listenWithPortFallback(explicitServer,{host:'127.0.0.1',preferredPort:occupiedPort,explicitPort:true}),
    error=>error?.code==='EADDRINUSE'&&/already in use/.test(error.message)
  );

  await close(fallbackServer);
  await close(blocker);
  console.log('LinkField v48.0 server startup fallback smoke test passed');
})().catch(error=>{console.error(error);process.exitCode=1});